Abstract

Purpose
To assess the effect of ADOA on the ON and OFF components of the photopic negative response (PhNR).
Methods
Twelve participants from 6 families with OPA1 ADOA and 16 age matched controls were recruited. Electrophysiological assessment involved long flash focal (20o) and full field ERGs using red flash (664 nm, 250 msec, 55 cd/m2, 2 Hz) on a rod saturating blue background (454 nm, 100 scot cd/m2); and brief xenon flash ERGs using red filter (Lee Filter “Terry Red”, max 300 µs flash duration, 1.69 cd.s.m-2, 4 Hz) over a continuous rod saturating blue background (Schott Glass Filter BG28, 206 scot cd/m2). Amplitudes (from peak and baseline to fixed time point) and implicit times of the ERG components were analysed.
Results
Mean amplitude (peak to fixed time) of the focal PhNR-ON were significantly (p < 0.05) reduced by 40% while the focal PhNR-OFF was completely eliminated. In the long duration full field ERG, the PhNR-ON and –OFF were reduced by 21% and 57% respectively. Subtraction of the grand averaged ERG of ADOA participants from that of the controls produced a difference plot with a nearly symmetrical loss in the PhNR-ON and OFF components of the focal ERG. ROC curve analysis showed focal PhNR-ON and OFF amplitudes performed better than their full field counterparts.
Conclusions
We show that OFF components of the photopic ERG were more severely affected in ADOA than ON components. Additionally, the focal PhNR-ON and –OFF components were more effective in assessing ADOA than their full field components.